Talk:Story Structure 102: Pure, Boring Theory/@comment-68.9.20.205-20150114182606/@comment-131.111.111.54-20150121133417
I don't know about the physics side of things, but the way you (Matt) are characterising evolution is... not right. Evolution is the change in heritable phenotypic traits over time. You say: "If neandrathal hadn't been wiped out through breeding and death they would be competing for the same resources we are and therefore our evolution would become stalled." Yes, there would have been resource competition, but that would simply have meant different selection pressures - perhaps for traits useful in resource competition and holding, or to take advantage of different resources / occupying different ecological niches (see, for example, a recent study on rapid evolution in Anolis lizards http://www.the-scientist.com/?articles.view/articleNo/41309/title/Rapid-Evolution-in-Real-Time/ ). Evolution doesn't become 'stalled', unless you think it has some target or end point (which it doesn't). "move the horse or the donkey forward in evolutionary terms (ability to survive better)" Natural selection acts on genes; it is the ability of an individual to pass their genes into future generations that denotes their 'fitness'. Who cares if a horse or donkey 'survives better'? If one horse is super sexy and mates with ALL the females, and they all have his babies, he can die the next day and will have much higher fitness than a long-lived male who gets no mates. Why doesn't such a horse exist? There's likely a trade-off between individual investment in survival and reproduction - especially as females produce only 1-2 foals per year - meaning there's selection for horses that can persist across a number of breeding seasons. "Only by breeding the best horses with the traits we like does evolution occur." No, breeding the best horses with the traits we like simply creates artificial selection for these traits; however, this doesn't always work due to the quirks of genetics (dominant/recessive alleles, linkages between traits that constrain their evolution, etc). "Just as if man and neandrathal were still getting it on we wouldn't be producing superiour beings." What do you mean by 'superior'? Sexual reproduction provides recombination, enabling genetic diversity, which - as the original commenter stated - underpins evolution. Genetic variation is the fuel that, through selection, powers evolutionary change. We don't know what would have happened if we had continued to interbreed with Neanderthals rather than them going extinct; I don't think there's even particularly clear data on why they went extinct while Homo sapiens flourished (although I may be wrong on this last point). "humans have left survival of the fittest for sexual evolution, what seems attractive to you sexually is what you try to breed with as oppose to the partner that would provide the best physical attributes to say stave off a harsh winter or carry heavy things long distance. These are no longer considered desirable traits to most and therefor we have entered a new type of evolution. A stagnant one." You make a number of strange assumptions here, most of which seem to stem from perhaps a misunderstanding about the definition of evolution. Sexual selection and natural selection are hugely powerful processes in evolutionary change. What are desirable traits now? What were previously desirable traits? Is there no crossover between these? Is there no crossover between traits considered attractive and traits involved with - for example - carrying heavy things long distance? How does our mating system (generally speaking, particularly in Western cultures, socially monogamous) affect the strength of sexual selection? Sorry about this wall of text. I'm a big fan of Harmon, but also I have a PhD in evolutionary biology so I couldn't stop myself...